Ultherapy uses ultrasound to target the 4.5 mm SMAS layer, making it popular...

https://web-wiki.win/index.php/Is_Ultherapy_FDA-Cleared_for_Lifting_or_Just_Tightening%3F

Ultherapy uses ultrasound to target the 4.5 mm SMAS layer, making it popular for lifting deep tissue without cutting. RF heats skin to around 40-45°C to boost collagen, great for mild tightening